Most known log roll winders cut the web while the web is in the air, rather than against a drum. Winders of this type are made by Fuji Tekko. As the knife cuts, it forces the web against a new core. However, because the tail of the web is not supported, the web, particularly thin webs, will not lay down smoothly against the core and wrinkles are produced on the outer wraps.
U.S. Pat. No. 4,775,110 to Welp et al. describes a winding system in which a complex cutting system is used to sever the web. One cutter perforates the web along a line and the web is braked to sever the web. Cutting is not performed on the fly. A hot wire can be used as a cutter and a vacuum can be used on the feed drum to secure the web.
Some continuous, high speed log roll winders which wind a continuous web of material around large rolls or drums transfer the web to a core on a wind-up spindle disposed against the drum. In one system, the winding is transferred from one wind-up spindle to another simply by moving the wind-up spindles against and away from the rotating drum. However, this requires precise timing. When transferring from the first wind-up spindle to the second wind-up spindle, the first wind-up spindle must be lifted off of the rotating drum before the cut end arrives. In doing this, the last portion of the web wrapped on the first wind-up spindle is uncontrolled and must be prevented from wrinkling. When transferring from the second to the first wind-up spindle, the first wind-up spindle must be moved against the rotating drum before the cut end arrives. Then the web is peeled off of its core on the second wind-up spindle while being prevented from wrinkling.
A roll winder made by Stahlkontor Maschinenbau GmbH winds a web at only one wind-up location. The web, drum, and wind-up roll stop for the web to be cut before the drum. Following the cut, the drum and roll of web resume turning to wind the tail of the web while the incoming web remains stopped. Next, the roll of web is unloaded, and an empty core is loaded in its place. Finally, the winder begins winding on the new core. This winder does not cut and transfer web on the fly. If the winder is used to wind on-line at the end of a continuous web maker, an accumulator is required to absorb incoming web during the cut and transfer, and web speeds are limited to 60 m/min to prevent tension problems. Additionally, the Stahlkontor machine cuts the web before it contacts the drum, leaving the web prone to wrinkling.
In the rewinder of U.S. Pat. No. 4,487,377 to Perini, after the web is cut, the leading edge of the web is permitted to fly rearwardly off of the main winding drum. This folded back portion is subsequently adhered to a core to begin winding another roll. No function for folding back the beginning portion of the web is disclosed.
U.S. Pat. No. 5,346,150 to Volin creates a gap between the cut ends of the web on the surface of the drum during the cut and transfer operation of the winder. The web is always supported during the cut and transfer. This enables the winder to cut and transfer the web on the fly at speeds of 137.2 m/min (450 ft/min) or more. This also permits winding and cutting the web against the drum and without wrinkling the web. This system uses two separate wind-up spindles on which the web is alternately wound.